U.S. patent application number 13/612462 was filed with the patent office on 2014-03-13 for confirmation of base station identification to improve handover.
This patent application is currently assigned to QUALCOMM Incorporated. The applicant listed for this patent is Qingxin Chen, Tom Chin, Guangming Shi, Ming Yang. Invention is credited to Qingxin Chen, Tom Chin, Guangming Shi, Ming Yang.
Application Number | 20140071938 13/612462 |
Document ID | / |
Family ID | 49237690 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140071938 |
Kind Code |
A1 |
Chin; Tom ; et al. |
March 13, 2014 |
CONFIRMATION OF BASE STATION IDENTIFICATION TO IMPROVE HANDOVER
Abstract
A method of wireless communication is presented. The method
includes receiving an operating frequency and base station
identification code (BSIC) for a neighboring base station,
determining an expected received signal based from the operating
frequency and BSIC, comparing a received signal with the expected
received signal, and reporting a result of the comparing.
Inventors: |
Chin; Tom; (San Diego,
CA) ; Yang; Ming; (San Diego, CA) ; Chen;
Qingxin; (Del Mar, CA) ; Shi; Guangming; (San
Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chin; Tom
Yang; Ming
Chen; Qingxin
Shi; Guangming |
San Diego
San Diego
Del Mar
San Diego |
CA
CA
CA
CA |
US
US
US
US |
|
|
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
49237690 |
Appl. No.: |
13/612462 |
Filed: |
September 12, 2012 |
Current U.S.
Class: |
370/331 |
Current CPC
Class: |
H04W 80/04 20130101;
H04W 36/0085 20180801; H04W 36/14 20130101; H04W 36/0061 20130101;
H04W 36/0083 20130101; H04W 84/12 20130101 |
Class at
Publication: |
370/331 |
International
Class: |
H04W 36/00 20060101
H04W036/00 |
Claims
1. A method of wireless communication, comprising: receiving an
operating frequency and base station identification code (BSIC) for
a neighboring base station; determining an expected received signal
based from the operating frequency and BSIC; comparing a received
signal with the expected received signal; and reporting a result of
the comparing.
2. The method of claim 1, in which: the expected received signal is
an expected synchronization channel (SCH) code word; and the
received signal is a received SCH code word.
3. The method of claim 2, in which the comparing comprises
correlating the expected SCH code word with the received SCH code
word.
4. The method of claim 1, in which the reporting comprises
reporting a verified BSIC to a sub-module of a connected RAT when
the result of the comparing is above a threshold.
5. The method of claim 1, in which the operating frequency and BSIC
are received in a neighboring base station list.
6. The method of claim 1, further comprising confirming an identity
of a base station sending the received signal using the BSIC.
7. An apparatus for wireless communication, comprising: means for
receiving an operating frequency and base station identification
code (BSIC) for a neighboring base station; means for determining
an expected received signal based from the operating frequency and
BSIC; means for comparing a received signal with the expected
received signal; and means for reporting a result of the
comparing.
8. The apparatus of claim 7, in which: the expected received signal
is an expected synchronization channel (SCH) code word; and the
received signal is a received SCH code word.
9. The apparatus of claim 8, in which the means for comparing
comprises means for correlating the expected SCH code word with the
received SCH code word.
10. The apparatus of claim 7, in which the means for reporting
comprises means for reporting a verified BSIC to a sub-module of a
connected RAT when the result of the comparing is above a
threshold.
11. The apparatus of claim 7, in which the operating frequency and
BSIC are received in a neighboring base station list.
12. The apparatus of claim 7, further comprising means for
confirming an identity of a base station sending the received
signal using the BSIC.
13. A computer program product for wireless communication in a
wireless network, comprising: a non-transitory computer-readable
medium having non-transitory program code recorded thereon, the
program code comprising: program code to receive an operating
frequency and base station identification code (BSIC) for a
neighboring base station; program code to determine an expected
received signal based from the operating frequency and BSIC;
program code to compare a received signal with the expected
received signal; and program code to report a result of the
comparing.
14. The computer program product of claim 13, in which: the
expected received signal is an expected synchronization channel
(SCH) code word; and the received signal is a received SCH code
word.
15. The computer program product of claim 14, in which the program
code to compare comprises program code to correlate the expected
SCH code word with the received SCH code word.
16. The computer program product of claim 13, in which the program
code to report comprises program code to report a verified BSIC to
a sub-module of a connected RAT when the result of the comparing is
above a threshold.
17. The computer program product of claim 13, in which the
operating frequency and BSIC are received in a neighboring base
station list.
18. The computer program product of claim 13, further comprising
program code to confirm an identity of a base station sending the
received signal using the BSIC.
19. An apparatus for wireless communication, comprising: a memory;
and at least one processor coupled to the memory, the at least one
processor being configured: to receive an operating frequency and
base station identification code (BSIC) for a neighboring base
station; to determine an expected received signal based from the
operating frequency and BSIC; to compare a received signal with the
expected received signal; and to report a result of the
comparing.
20. The apparatus of claim 19, in which: the expected received
signal is an expected synchronization channel (SCH) code word; and
the received signal is a received SCH code word.
21. The apparatus of claim 20, in which the at least one processor
is further configured to correlate the expected SCH code word with
the received SCH code word.
22. The apparatus of claim 19, in which the at least one processor
is further configured to report a verified BSIC to a sub-module of
a connected RAT when the result of the comparing is above a
threshold.
23. The apparatus of claim 19, in which the operating frequency and
BSIC are received in a neighboring base station list.
24. The apparatus of claim 19, in which the at least one processor
is further configured to confirm an identity of a base station
sending the received signal using the BSIC.
Description
BACKGROUND
[0001] 1. Field
[0002] Aspects of the present disclosure relate generally to
wireless communication systems, and more particularly, to
confirming base station identification prior to a handover in a
TD-SCDMA network.
[0003] 2. Background
[0004] Wireless communication networks are widely deployed to
provide various communication services such as telephony, video,
data, messaging, broadcasts, and so on. Such networks, which are
usually multiple access networks, support communications for
multiple users by sharing the available network resources. One
example of such a network is the Universal Terrestrial Radio Access
Network (UTRAN). The UTRAN is the radio access network (RAN)
defined as a part of the Universal Mobile Telecommunications System
(UMTS), a third generation (3G) mobile phone technology supported
by the 3rd Generation Partnership Project (3GPP). The UMTS, which
is the successor to Global System for Mobile Communications (GSM)
technologies, currently supports various air interface standards,
such as Wideband-Code Division Multiple Access (W-CDMA), Time
Division-Code Division Multiple Access (TD-CDMA), and Time
Division-Synchronous Code Division Multiple Access (TD-SCDMA). For
example, China is pursuing TD-SCDMA as the underlying air interface
in the UTRAN architecture with its existing GSM infrastructure as
the core network. The UMTS also supports enhanced 3G data
communications protocols, such as High Speed Packet Access (HSPA),
which provides higher data transfer speeds and capacity to
associated UMTS networks. HSPA is a collection of two mobile
telephony protocols, High Speed Downlink Packet Access (HSDPA) and
High Speed Uplink Packet Access (HSUPA), that extends and improves
the performance of existing wideband protocols.
[0005] As the demand for mobile broadband access continues to
increase, research and development continue to advance the UMTS
technologies not only to meet the growing demand for mobile
broadband access, but to advance and enhance the user experience
with mobile communications.
SUMMARY
[0006] According to an aspect, a method of wireless communication
is presented. The method includes receiving an operating frequency
and base station identification code (BSIC) for a neighboring base
station. The method also includes determining an expected received
signal based from the operating frequency and BSIC. The method
further includes comparing a received signal with the expected
received signal. The method still further includes reporting a
result of the comparing.
[0007] According to another aspect, an apparatus for wireless
communication is presented. The apparatus includes means for
receiving an operating frequency and BSIC for a neighboring base
station. The apparatus also includes means for determining an
expected received signal based from the operating frequency and
BSIC. The apparatus further includes means for comparing a received
signal with the expected received signal. The apparatus still
further includes means for reporting a result of the comparing.
[0008] According to yet another aspect a computer program product
for wireless communication in a wireless network. The computer
program product includes a non-transitory computer-readable medium
having non-transitory program code recorded thereon. The program
code includes program code to receive an operating frequency and
BSIC for a neighboring base station. The program code also includes
program code to determine an expected received signal based from
the operating frequency and BSIC. The program code further includes
program code to compare a received signal with the expected
received signal. The program code still further includes program
code to report a result of the comparing.
[0009] According to still yet another aspect, an apparatus for
wireless communication is presented. The apparatus includes a
memory and a processor(s) coupled to the memory. The processor
being configured to receive an operating frequency and BSIC for a
neighboring base station. The processor is also configured to
determine an expected received signal based from the operating
frequency and BSIC. The processor is further configured to compare
a received signal with the expected received signal. The processor
is still further configured to report a result of the
comparing.
[0010] This has outlined, rather broadly, the features and
technical advantages of the present disclosure in order that the
detailed description that follows may be better understood.
Additional features and advantages of the disclosure will be
described below. It should be appreciated by those skilled in the
art that this disclosure may be readily utilized as a basis for
modifying or designing other structures for carrying out the same
purposes of the present disclosure. It should also be realized by
those skilled in the art that such equivalent constructions do not
depart from the teachings of the disclosure as set forth in the
appended claims. The novel features, which are believed to be
characteristic of the disclosure, both as to its organization and
method of operation, together with further objects and advantages,
will be better understood from the following description when
considered in connection with the accompanying figures. It is to be
expressly understood, however, that each of the figures is provided
for the purpose of illustration and description only and is not
intended as a definition of the limits of the present
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a block diagram conceptually illustrating an
example of a telecommunications system.
[0012] FIG. 2 is a block diagram conceptually illustrating an
example of a frame structure in a telecommunications system.
[0013] FIG. 3 is a block diagram conceptually illustrating an
example of a node B in communication with a UE in a
telecommunications system.
[0014] FIG. 4 is a block diagram illustrating a method for
verifying a neighbor base station identification code in a
multi-RAT UE according to an aspect of the present disclosure.
[0015] FIG. 5 is a block diagram illustrating a method for
confirming a base station identification code according to an
aspect of the present disclosure.
[0016] FIG. 6 is a diagram illustrating an example of a hardware
implementation for an apparatus employing a processing system
according to one aspect of the present disclosure.
DETAILED DESCRIPTION
[0017] The detailed description set forth below, in connection with
the appended drawings, is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of the various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well-known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0018] Turning now to FIG. 1, a block diagram is shown illustrating
an example of a telecommunications system 100. The various concepts
presented throughout this disclosure may be implemented across a
broad variety of telecommunication systems, network architectures,
and communication standards. By way of example and without
limitation, the aspects of the present disclosure illustrated in
FIG. 1 are presented with reference to a UMTS system employing a
TD-SCDMA standard. In this example, the UMTS system includes a
(radio access network) RAN 102 (e.g., UTRAN) that provides various
wireless services including telephony, video, data, messaging,
broadcasts, and/or other services. The RAN 102 may be divided into
a number of Radio Network Subsystems (RNSs) such as an RNS 107,
each controlled by a Radio Network Controller (RNC) such as an RNC
106. For clarity, only the RNC 106 and the RNS 107 are shown;
however, the RAN 102 may include any number of RNCs and RNSs in
addition to the RNC 106 and RNS 107. The RNC 106 is an apparatus
responsible for, among other things, assigning, reconfiguring and
releasing radio resources within the RNS 107. The RNC 106 may be
interconnected to other RNCs (not shown) in the RAN 102 through
various types of interfaces such as a direct physical connection, a
virtual network, or the like, using any suitable transport
network.
[0019] The geographic region covered by the RNS 107 may be divided
into a number of cells, with a radio transceiver apparatus serving
each cell. A radio transceiver apparatus is commonly referred to as
a node B in UMTS applications, but may also be referred to by those
skilled in the art as a base station (BS), a base transceiver
station (BTS), a radio base station, a radio transceiver, a
transceiver function, a basic service set (BSS), an extended
service set (ESS), an access point (AP), or some other suitable
terminology. For clarity, two node Bs 108 are shown; however, the
RNS 107 may include any number of wireless node Bs. The node Bs 108
provide wireless access points to a core network 104 for any number
of mobile apparatuses. Examples of a mobile apparatus include a
cellular phone, a smart phone, a session initiation protocol (SIP)
phone, a laptop, a notebook, a netbook, a smartbook, a personal
digital assistant (PDA), a satellite radio, a global positioning
system (GPS) device, a multimedia device, a video device, a digital
audio player (e.g., MP3 player), a camera, a game console, or any
other similar functioning device. The mobile apparatus is commonly
referred to as user equipment (UE) in UMTS applications, but may
also be referred to by those skilled in the art as a mobile station
(MS), a subscriber station, a mobile unit, a subscriber unit, a
wireless unit, a remote unit, a mobile device, a wireless device, a
wireless communications device, a remote device, a mobile
subscriber station, an access terminal (AT), a mobile terminal, a
wireless terminal, a remote terminal, a handset, a terminal, a user
agent, a mobile client, a client, or some other suitable
terminology. For illustrative purposes, three UEs 110 are shown in
communication with the node Bs 108. The downlink (DL), also called
the forward link, refers to the communication link from a node B to
a UE, and the uplink (UL), also called the reverse link, refers to
the communication link from a UE to a node B.
[0020] The core network 104, as shown, includes a GSM core network.
However, as those skilled in the art will recognize, the various
concepts presented throughout this disclosure may be implemented in
a RAN, or other suitable access network, to provide UEs with access
to types of core networks other than GSM networks.
[0021] In this example, the core network 104 supports
circuit-switched services with a mobile switching center (MSC) 112
and a gateway MSC (GMSC) 114. One or more RNCs, such as the RNC
106, may be connected to the MSC 112. The MSC 112 is an apparatus
that controls call setup, call routing, and UE mobility functions.
The MSC 112 also includes a visitor location register (VLR) (not
shown) that contains subscriber-related information for the
duration that a UE is in the coverage area of the MSC 112. The GMSC
114 provides a gateway through the MSC 112 for the UE to access a
circuit-switched network 116. The GMSC 114 includes a home location
register (HLR) (not shown) containing subscriber data, such as the
data reflecting the details of the services to which a particular
user has subscribed. The HLR is also associated with an
authentication center (AuC) that contains subscriber-specific
authentication data. When a call is received for a particular UE,
the GMSC 114 queries the HLR to determine the UE's location and
forwards the call to the particular MSC serving that location.
[0022] The core network 104 also supports packet-data services with
a serving GPRS support node (SGSN) 118 and a gateway GPRS support
node (GGSN) 120. GPRS, which stands for General Packet Radio
Service, is designed to provide packet-data services at speeds
higher than those available with standard GSM circuit-switched data
services. The GGSN 120 provides a connection for the RAN 102 to a
packet-based network 122. The packet-based network 122 may be the
Internet, a private data network, or some other suitable
packet-based network. The primary function of the GGSN 120 is to
provide the UEs 110 with packet-based network connectivity. Data
packets are transferred between the GGSN 120 and the UEs 110
through the SGSN 118, which performs primarily the same functions
in the packet-based domain as the MSC 112 performs in the
circuit-switched domain.
[0023] The UMTS air interface is a spread spectrum Direct-Sequence
Code Division Multiple Access (DS-CDMA) system. The spread spectrum
DS-CDMA spreads user data over a much wider bandwidth through
multiplication by a sequence of pseudorandom bits called chips. The
TD-SCDMA standard is based on such direct sequence spread spectrum
technology and additionally calls for a time division duplexing
(TDD), rather than a frequency division duplexing (FDD) as used in
many FDD mode UMTS/W-CDMA systems. TDD uses the same carrier
frequency for both the uplink (UL) and downlink (DL) between a node
B 108 and a UE 110, but divides uplink and downlink transmissions
into different time slots in the carrier.
[0024] FIG. 2 shows a frame structure 200 for a TD-SCDMA carrier.
The TD-SCDMA carrier, as illustrated, has a frame 202 that is 10 ms
in length. The chip rate in TD-SCDMA is 1.28 Mcps. The frame 202
has two 5 ms subframes 204, and each of the subframes 204 includes
seven time slots, TS0 through TS6. The first time slot, TS0, is
usually allocated for downlink communication, while the second time
slot, TS1, is usually allocated for uplink communication. The
remaining time slots, TS2 through TS6, may be used for either
uplink or downlink, which allows for greater flexibility during
times of higher data transmission times in either the uplink or
downlink directions. A downlink pilot time slot (DwPTS) 206, a
guard period (GP) 208, and an uplink pilot time slot (UpPTS) 210
(also known as the uplink pilot channel (UpPCH)) are located
between TS0 and TS1. Each time slot, TS0-TS6, may allow data
transmission multiplexed on a maximum of 16 code channels. Data
transmission on a code channel includes two data portions 212 (each
with a length of 352 chips) separated by a midamble 214 (with a
length of 144 chips) and followed by a guard period (GP) 216 (with
a length of 16 chips). The midamble 214 may be used for features,
such as channel estimation, while the guard period 216 may be used
to avoid inter-burst interference. Also transmitted in the data
portion is some Layer 1 control information, including
Synchronization Shift (SS) bits 218. Synchronization Shift bits 218
only appear in the second part of the data portion. The
Synchronization Shift bits 218 immediately following the midamble
can indicate three cases: decrease shift, increase shift, or do
nothing in the upload transmit timing. The positions of the SS bits
218 are not generally used during uplink communications.
[0025] FIG. 3 is a block diagram of a node B 310 in communication
with a UE 350 in a RAN 300, where the RAN 300 may be the RAN 102 in
FIG. 1, the node B 310 may be the node B 108 in FIG. 1, and the UE
350 may be the UE 110 in FIG. 1. In the downlink communication, a
transmit processor 320 may receive data from a data source 312 and
control signals from a controller/processor 340. The transmit
processor 320 provides various signal processing functions for the
data and control signals, as well as reference signals (e.g., pilot
signals). For example, the transmit processor 320 may provide
cyclic redundancy check (CRC) codes for error detection, coding and
interleaving to facilitate forward error correction (FEC), mapping
to signal constellations based on various modulation schemes (e.g.,
binary phase-shift keying (BPSK), quadrature phase-shift keying
(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude
modulation (M-QAM), and the like), spreading with orthogonal
variable spreading factors (OVSF), and multiplying with scrambling
codes to produce a series of symbols. Channel estimates from a
channel processor 344 may be used by a controller/processor 340 to
determine the coding, modulation, spreading, and/or scrambling
schemes for the transmit processor 320. These channel estimates may
be derived from a reference signal transmitted by the UE 350 or
from feedback contained in the midamble 214 (FIG. 2) from the UE
350. The symbols generated by the transmit processor 320 are
provided to a transmit frame processor 330 to create a frame
structure. The transmit frame processor 330 creates this frame
structure by multiplexing the symbols with a midamble 214 (FIG. 2)
from the controller/processor 340, resulting in a series of frames.
The frames are then provided to a transmitter 332, which provides
various signal conditioning functions including amplifying,
filtering, and modulating the frames onto a carrier for downlink
transmission over the wireless medium through smart antennas 334.
The smart antennas 334 may be implemented with beam steering
bidirectional adaptive antenna arrays or other similar beam
technologies.
[0026] At the UE 350, a receiver 354 receives the downlink
transmission through an antenna 352 and processes the transmission
to recover the information modulated onto the carrier. The
information recovered by the receiver 354 is provided to a receive
frame processor 360, which parses each frame, and provides the
midamble 214 (FIG. 2) to a channel processor 394 and the data,
control, and reference signals to a receive processor 370. The
receive processor 370 then performs the inverse of the processing
performed by the transmit processor 320 in the node B 310. More
specifically, the receive processor 370 descrambles and despreads
the symbols, and then determines the most likely signal
constellation points transmitted by the node B 310 based on the
modulation scheme. These soft decisions may be based on channel
estimates computed by the channel processor 394. The soft decisions
are then decoded and deinterleaved to recover the data, control,
and reference signals. The CRC codes are then checked to determine
whether the frames were successfully decoded. The data carried by
the successfully decoded frames will then be provided to a data
sink 372, which represents applications running in the UE 350
and/or various user interfaces (e.g., display). Control signals
carried by successfully decoded frames will be provided to a
controller/processor 390. When frames are unsuccessfully decoded by
the receiver processor 370, the controller/processor 390 may also
use an acknowledgement (ACK) and/or negative acknowledgement (NACK)
protocol to support retransmission requests for those frames.
[0027] In the uplink, data from a data source 378 and control
signals from the controller/processor 390 are provided to a
transmit processor 380. The data source 378 may represent
applications running in the UE 350 and various user interfaces
(e.g., keyboard). Similar to the functionality described in
connection with the downlink transmission by the node B 310, the
transmit processor 380 provides various signal processing functions
including CRC codes, coding and interleaving to facilitate FEC,
mapping to signal constellations, spreading with OVSFs, and
scrambling to produce a series of symbols. Channel estimates,
derived by the channel processor 394 from a reference signal
transmitted by the node B 310 or from feedback contained in the
midamble transmitted by the node B 310, may be used to select the
appropriate coding, modulation, spreading, and/or scrambling
schemes. The symbols produced by the transmit processor 380 will be
provided to a transmit frame processor 382 to create a frame
structure. The transmit frame processor 382 creates this frame
structure by multiplexing the symbols with a midamble 214 (FIG. 2)
from the controller/processor 390, resulting in a series of frames.
The frames are then provided to a transmitter 356, which provides
various signal conditioning functions including amplification,
filtering, and modulating the frames onto a carrier for uplink
transmission over the wireless medium through the antenna 352.
[0028] The uplink transmission is processed at the node B 310 in a
manner similar to that described in connection with the receiver
function at the UE 350. A receiver 335 receives the uplink
transmission through the antenna 334 and processes the transmission
to recover the information modulated onto the carrier. The
information recovered by the receiver 335 is provided to a receive
frame processor 336, which parses each frame, and provides the
midamble 214 (FIG. 2) to the channel processor 344 and the data,
control, and reference signals to a receive processor 338. The
receive processor 338 performs the inverse of the processing
performed by the transmit processor 380 in the UE 350. The data and
control signals carried by the successfully decoded frames may then
be provided to a data sink 339 and the controller/processor,
respectively. If some of the frames were unsuccessfully decoded by
the receive processor, the controller/processor 340 may also use an
acknowledgement (ACK) and/or negative acknowledgement (NACK)
protocol to support retransmission requests for those frames.
[0029] The controller/processors 340 and 390 may be used to direct
the operation at the node B 310 and the UE 350, respectively. For
example, the controller/processors 340 and 390 may provide various
functions including timing, peripheral interfaces, voltage
regulation, power management, and other control functions. The
computer readable media of memories 342 and 392 may store data and
software for the node B 310 and the UE 350, respectively. For
example, the memory 392 of the UE 350 may store a base station
identity code identification module 391 which, when executed by the
controller/processor 390, configures the UE 350 for determining an
expected synchronization channel code word based on the operating
frequency and base station identification code of a base station. A
scheduler/processor 346 at the node B 310 may be used to allocate
resources to the UEs and schedule downlink and/or uplink
transmissions for the UEs.
Confirmation of Base Station Identification to Improve Handover
[0030] A potential inter-RAT handover may specify for a UE to
perform measurements to confirm and re-confirm the identification
code of a neighboring base station. In a multi-RAT capable user
equipment (UE), when a UE is performing inter-RAT measurements for
a potential inter-RAT handover, a single receiver UE may not have
sufficient idle time slots to confirm and re-confirm the
identification code of a neighboring base station. For example,
when performing inter-RAT measurements for a TD-SCDMA to GSM
handover, the UE may not have sufficient idle time slots to confirm
and re-confirm the identification code of a neighboring GSM base
station. It should be noted that in the present disclosure a UE
refers to a multi-RAT UE.
[0031] According to an aspect of the present disclosure, a UE may
use the information from a neighbor base station list provided by a
serving base station of a first RAT, such as a TD-SCDMA base
station, to find a relationship between an operating frequency and
a base station identification code (BSIC) of neighboring base
stations of a second RAT, such as GSM base stations. In this
aspect, the UE may use the relationship to determine an expected
synchronization channel (SCH) code word. Moreover, the UE may
receive a synchronization code word of a neighbor base station
while performing inter-RAT measurements. After receiving the actual
synchronization channel code word, the UE may compare the received
synchronization channel code word with the expected synchronization
channel code word. The UE may perform the measurement reporting
specified for an inter-RAT handover if the results of the
comparison are above a threshold.
[0032] According to an aspect of the present disclosure, the UE may
use a reduced number of idle time slots for decoding a base station
identification code by comparing an actual received code word to
the expected code word. The reduced number of idle time slots may
improve inter-RAT measurements prior to a handover. In a
conventional system, the UE decodes the synchronization code word
during idle time slots to obtain the base station identification
code. In one aspect of the present disclosure, the UE does not
decode the synchronization code word during idle time slots.
Rather, the expected synchronization code word is determined from
the relationship between an operating frequency and a base station
identification code. The UE may determine that the decoding of the
synchronization code word is successful when the correlation
between the expected synchronization code word and the received
synchronization code word is above a threshold.
[0033] In some cases, a UE may include sub-modules for each RAT.
For example, a UE may include a TD-SCDMA sub-module and a GSM
sub-module. When the UE is connected to a first RAT, such as
TD-SCDMA, the first RAT sub-module may receive a neighbor base
station list from the first RAT. The neighbor base station list
includes a list of neighbor base stations of a second RAT, such as
GSM. The neighbor base station list may also include the operating
frequency (e.g., absolute radio frequency channel number (ARFCN))
and the base station identification code of each neighbor base
station.
[0034] According to an aspect of the present disclosure, a first
RAT sub-module may provide the information in the neighbor base
station list to a second RAT sub-module. The second RAT sub-module
may generate an expected synchronization channel code word based on
the operating frequency and base station identification code of a
specific neighbor base station. Furthermore, the UE (e.g., second
RAT sub-module) may perform inter-RAT measurements of the specific
neighbor base station and receive an actual synchronization channel
code word. The UE may then correlate the received synchronization
channel code word with the expected synchronization channel code
word to determine whether the synchronization channel decoding is
successful.
[0035] Specifically, the UE determines whether the correlation of
the received synchronization channel code word with the expected
synchronization channel code word is above or below a threshold.
More specifically, the UE may determine that the synchronization
channel decoding was successful and may report, to the first RAT
sub-module, that the neighbor base station identification code was
verified if the correlation is above a threshold. Furthermore, the
UE may determine that the synchronization channel decoding failed
and may report, to the first RAT sub-module, that the neighbor base
station identification code was not verified if the correlation is
below a threshold.
[0036] FIG. 4 is block diagram illustrating verifying a neighbor
base station identification code in a UE 400 according to an aspect
of the present disclosure. As shown in FIG. 4, the UE 400 may
include a first RAT sub-module 420 and a second RAT sub-module 422.
The first RAT sub-module 420 may receive a neighbor base station
list from the first RAT and may transmit the received neighbor base
station list to the second RAT sub-module 422, as shown in block
402. The neighbor base station list may include a list of neighbor
base stations of the second RAT. The neighbor base station list may
also include the operating frequency and the base station
identification code of each base station of the second RAT. The
second RAT sub-module 422 may generate an expected synchronization
code word based on a relationship between the operating frequency
and base station identification code of a specific base station of
the second RAT, as shown in block 404. It should be noted that
according to aspects of the present disclosure, the second RAT
sub-module 422 may generate an expected synchronization code for
each base station on the neighboring base station list or specific
base stations on the neighboring base station list.
[0037] Additionally, the second RAT sub-module 422 may perform
inter-RAT measurements for a base station of the second RAT, as
shown in block 406. After performing inter-RAT measurements of a
base station of the second RAT (block 406), the second RAT
sub-module 422 may correlate the expected synchronization code word
with a received synchronization code word of the base station of
the second RAT, as shown in block 408. The UE may then determine if
the correlation is above or below a threshold, as shown in block
410. Finally, the UE may inform the first RAT sub-module 420 if the
base station identification code was verified or not verified based
on the correlation. That is, if the correlation is above a
threshold, the base station identification code is verified and the
synchronization channel decoding is deemed successful.
Alternatively, if the correlation is less than a threshold, the
base station identification code is not verified and the
synchronization channel decoding is deemed unsuccessful.
[0038] Aspects of the present disclosure improve the success rate
for the synchronization channel decoding, reduce the probability of
base station identification code identification/reconfirmation
failure, and also reduce the latency of the synchronization channel
decoding procedure. That is, the aspects of the present disclosure
improve the success rate of an inter-RAT handover.
[0039] FIG. 5 shows a wireless communication method 500 according
to one aspect of the disclosure. A UE receives an operating
frequency and base station identification code (BSIC) for a
neighboring base station as shown in block 502. The UE also
determines an expected received signal based from the operating
frequency and BSIC, as shown in block 504. Furthermore, the UE
compares a received signal with the expected received signal, as
shown in bock 506. Finally, the UE reports a result of the
comparison, as shown in block 508.
[0040] FIG. 6 is a diagram illustrating an example of a hardware
implementation for an apparatus 600 employing a processing system
614. The processing system 614 may be implemented with a bus
architecture, represented generally by the bus 624. The bus 624 may
include any number of interconnecting buses and bridges depending
on the specific application of the processing system 614 and the
overall design constraints. The bus 624 links together various
circuits including one or more processors and/or hardware modules,
represented by the processor 622 the modules 602, 604, 606, 608,
and the computer-readable medium 626. The bus 624 may also link
various other circuits such as timing sources, peripherals, voltage
regulators, and power management circuits, which are well known in
the art, and therefore, will not be described any further.
[0041] The apparatus includes a processing system 614 coupled to a
transceiver 630. The transceiver 630 is coupled to one or more
antennas 620. The transceiver 630 enables communicating with
various other apparatus over a transmission medium. The processing
system 614 includes a processor 622 coupled to a computer-readable
medium 626. The processor 622 is responsible for general
processing, including the execution of software stored on the
computer-readable medium 626. The software, when executed by the
processor 622, causes the processing system 614 to perform the
various functions described for any particular apparatus. The
computer-readable medium 626 may also be used for storing data that
is manipulated by the processor 622 when executing software.
[0042] The processing system 614 includes a receiving module 602
for receiving an operating frequency and base station
identification code (BSIC) for a neighboring base station. The
processing system 614 includes a determining module 604 for
determining an expected received signal based from the operating
frequency and BSIC. The processing system 614 also includes a
comparing module 606 for comparing a received signal with the
expected signal. The processing system 614 further includes a
reporting module 608 for reporting as result of the comparing. The
modules may be software modules running in the processor 622,
resident/stored in the computer-readable medium 626, one or more
hardware modules coupled to the processor 622, or some combination
thereof. The processing system 614 may be a component of the UE 350
and may include the memory 392, and/or the controller/processor
390.
[0043] In one configuration, an apparatus such as a UE is
configured for wireless communication including means for
receiving, means for determining, means for comparing, and means
for reporting. In one aspect, the above means may be the antennas
352, the receiver 354, the channel processor 394, the receive frame
processor 360, the receive processor 370, the transmitter 356, the
transmit frame processor 382, the transmit processor 380, the
controller/processor 390, the memory 392, synchronization channel
code word estimation module 391, receiving module 602, determining
module 604, comparing module 606, reporting module 608, and/or the
processing system 614 configured to perform the functions recited
by the aforementioned means. In another aspect, the aforementioned
means may be a module or any apparatus configured to perform the
functions recited by the aforementioned means.
[0044] Several aspects of a telecommunications system has been
presented with reference to TD-SCDMA systems. As those skilled in
the art will readily appreciate, various aspects described
throughout this disclosure may be extended to other
telecommunication systems, network architectures and communication
standards. By way of example, various aspects may be extended to
other UMTS systems such as W-CDMA, High Speed Downlink Packet
Access (HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed
Packet Access Plus (HSPA+) and TD-CDMA. Various aspects may also be
extended to systems employing Long Term Evolution (LTE) (in FDD,
TDD, or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both
modes), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile
Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE
802.20, Ultra-Wideband (UWB), Bluetooth, and/or other suitable
systems. The actual telecommunication standard, network
architecture, and/or communication standard employed will depend on
the specific application and the overall design constraints imposed
on the system.
[0045] Several processors have been described in connection with
various apparatuses and methods. These processors may be
implemented using electronic hardware, computer software, or any
combination thereof. Whether such processors are implemented as
hardware or software will depend upon the particular application
and overall design constraints imposed on the system. By way of
example, a processor, any portion of a processor, or any
combination of processors presented in this disclosure may be
implemented with a microprocessor, microcontroller, digital signal
processor (DSP), a field-programmable gate array (FPGA), a
programmable logic device (PLD), a state machine, gated logic,
discrete hardware circuits, and other suitable processing
components configured to perform the various functions described
throughout this disclosure. The functionality of a processor, any
portion of a processor, or any combination of processors presented
in this disclosure may be implemented with software being executed
by a microprocessor, microcontroller, DSP, or other suitable
platform.
[0046] Software shall be construed broadly to mean instructions,
instruction sets, code, code segments, program code, programs,
subprograms, software modules, applications, software applications,
software packages, routines, subroutines, objects, executables,
threads of execution, procedures, functions, etc., whether referred
to as software, firmware, middleware, microcode, hardware
description language, or otherwise. The software may reside on a
computer-readable medium. A computer-readable medium may include,
by way of example, memory such as a magnetic storage device (e.g.,
hard disk, floppy disk, magnetic strip), an optical disk (e.g.,
compact disc (CD), digital versatile disc (DVD)), a smart card, a
flash memory device (e.g., card, stick, key drive), random access
memory (RAM), read only memory (ROM), programmable ROM (PROM),
erasable PROM (EPROM), electrically erasable PROM (EEPROM), a
register, or a removable disk. Although memory is shown separate
from the processors in the various aspects presented throughout
this disclosure, the memory may be internal to the processors
(e.g., cache or register).
[0047] Computer-readable media may be embodied in a
computer-program product. By way of example, a computer-program
product may include a computer-readable medium in packaging
materials. Those skilled in the art will recognize how best to
implement the described functionality presented throughout this
disclosure depending on the particular application and the overall
design constraints imposed on the overall system.
[0048] It is to be understood that the specific order or hierarchy
of steps in the methods disclosed is an illustration of exemplary
processes. Based upon design preferences, it is understood that the
specific order or hierarchy of steps in the methods may be
rearranged. The accompanying method claims present elements of the
various steps in a sample order, and are not meant to be limited to
the specific order or hierarchy presented unless specifically
recited therein.
[0049] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language of the
claims, wherein reference to an element in the singular is not
intended to mean "one and only one" unless specifically so stated,
but rather "one or more." Unless specifically stated otherwise, the
term "some" refers to one or more. A phrase referring to "at least
one of" a list of items refers to any combination of those items,
including single members. As an example, "at least one of: a, b, or
c" is intended to cover: a; b; c; a and b; a and c; b and c; and a,
b and c. All structural and functional equivalents to the elements
of the various aspects described throughout this disclosure that
are known or later come to be known to those of ordinary skill in
the art are expressly incorporated herein by reference and are
intended to be encompassed by the claims. Moreover, nothing
disclosed herein is intended to be dedicated to the public
regardless of whether such disclosure is explicitly recited in the
claims. No claim element is to be construed under the provisions of
35 U.S.C. .sctn.112, sixth paragraph, unless the element is
expressly recited using the phrase "means for" or, in the case of a
method claim, the element is recited using the phrase "step
for."
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